Surge chamber



June 3, 1969 M. E. PHELPS ET AL 3,447,557

SURGE CHAMBER Filed Feb. 10, 1967 II 0 n 1 4/; II II. I! I! INVENTORS.M0870 5 PA/l PS,

& a 5 O. W W m United States Patent Oihce 3,447,557 Patented June 3,1969 Tommy 0. Bell, P.0. Box 203, Hallsville, Tex. 75 650 Filed Feb. 10,1967, Ser. No. 615,195 Int. Cl. E03b /00 US. Cl. 137-207 6 ClaimsABSTRACT OF THE DISCLOSURE A surge tank, for smoothing pressure changesin a pumped liquid, having a continuous curved wall with a liquid inlettherein and a tengential feed conduit connected to the inlet causing theentering liquid to rotate about the curved wall trapping air in the topof and centrally of the tank. A tank outlet is arranged to exhaustliquid from the peripheral area near the bottom of the curved wall so asto prevent loss of trapped air from the center of the tank. Desirably aninner chamber is disposed within the tank, and is also closed at the topbut has communicating openings near its bottom to permit entry of bothair and liquid from the tank to the inner chamber, Thus, dual airtrapping, compression chambers are provided to assist the swirlingliquid in eliminating pressure variations at the liquid outlet.

This invention relates to surge chambers and more particularly to animproved surge tank utilizing both the rotation, or spinning, of aliquid and the compression of air, preferably in at least two chambers,to absorb shocks and smooth out pressure variations of a pumped liquid.

Surge tanks as presently known have many applications including theabsorption of irregularities of flow in main liquid supply lines, thesmoothing out of pumping pressure variations where water is pumped athigh pressures for spraying vegetation, fruit orchards and the like, andthe spraying of disinfectants onto crops.

It is a primary object of the present invention to provide an improvedsurge chamber which operates to spin the entering liquid and trap airabove the spinning liquid both serving to smooth pressure variations ofthe incoming liquid.

Another object of the invention is to provide a surge chamber, havingthe above described characteristics, which is so constructed as to avoidlosing air trapped above the spinning liquid.

An important object of the invention is to provide at least two airtrapping chambers which augment each other and the spinning liquid toiron out pressure surges.

A further object of the present invention is to provide an improvedsurge chamber, having the above described characteristics, which employsno moving parts.

Yet another object of the invention is to provide an improved surgechamber which is of simple construction, easy and economical tomanufacture, and eflicient in operation.

The novel features that are considered characteristic of the inventionare set forth with particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation,together with additional objects and advantages thereof, will best beunderstood from the following description of specific embodiments whenread in connection with the accompanying drawing, wherein like referencecharacters indicate like parts throughout the several figures and inwhich:

FIG. 1 is a vertical axial sectional view of an improved surge chamberaccording to the present invention;

FIGS. 2 and 3 are horizontal sectional views taken on lines 22 and 3-3,respectively, of FIG. 1, and looking in the direction of the arrows;

FIG. 4 is a vertical axial section of another embodiment of theinvention; and

FIG. 5 is a vertical sectional view similar to FIGS. 1 and 4 of stillanother embodiment of the invention.

Referring more particularly to the drawings, in FIGS. 1-3 is illustrateda preferred embodiment of the invention as comprising a surge chamber10, or tank, formed of metal such as aluminum, brass, or any othersuitable common noncorrosive, metal or alloy. Tank 10 has a cylindricalsidewall 12 integrally bonded to a continuous top wall 14, and a bottomwall 16 in which is an outlet 18. In the sidewall is an inlet 20positioned considerably below the top wall and somewhat above the bottomwall. Integrally bonded to the inlet is a liquid feed conduit 22disposed at a tangent to the cylindrical inner surface of the sidewallso that entering liquid under pressure will swirl around the innersurface of the sidewall. This rotational movement within the chamber, bycentrifugal force, throws the liquid against the sidewall so that air istrapped under the top wall, the surface of the liquid within the chambertaking an inverted conical shape, not shown, whose slope depends uponthe speed of rotation. Swirling of the liquid forces the trapped airtoward the center of the chamber and against the outer surface of aninner cylindrical tube 24 integrally bonded to the top wall. Thecylindrical tube 24 and the top wall form an inner chamber 26 whichcommunicates with the outer chamber, represented by the referencecharacter 28, by a purality of spaced openings 30 positioned at thelower part of the tube 24 between its bottom and the level of the inlet20.

A second wall 32 is spaced above the bottom wall 16 and is of smallerdiameter so that a space 34 is provided at its periphery to permitegress of liquid downwardly along the inner surface of the sidewall 12.In the space between the first and second bottom walls are disposed aplurality of curved vanes 36 which extend from the periphery of thesecond bottom wall at least to and slightly within the periphery of theoutlet 18. The vanes are curved in such direction as to smoothly leadexiting liquid from the space 34 to the outlet 18 guiding such liquid atthe start in the same direction as its rotation, but with greatercurvature so as to gradually turn the liquid toward the center of thesurge chamber and into the central outlet. Thus, a path exists, for thedischarge of liquid through space 34 under the second bottom wall 32 andalong the vanes 36, which is so arranged as to be completely spaced fromthe central portion of the surge tank 10 and the centrally disposed airtrapped therein.

The operation of the surge chamber is as follows. Liquid from a pump isforced at high pressure along the feed conduit 22 and enter the surgetank through inlet 20 spinning about the outer chamber 28. As theangular velocity of the liquid increases with surges in pump pressure,the liquid within the outer chamber 28 rise and is held against thesidewall 12 by centrifugal force, the upper surface of the liquidadopting the form of an inverted cone. As pressure builds up during suchsurges, the air within both chambers 26 and 28 is forced to the top, andin the outer chamber takes the same conical shape as the liquid and ispressed inwardly against the central cylinder 24. With extremely highpressure surges some air escapes from the top of the outer chamber 28descending along the inner cylinder 24 where it pases through theapertures 30, floats to the top of liquid in the inner chamber 26, andremains trapped therein. During this course of movement, the air in bothchambers is kept away from the exit space 34 and cannot escape the surgetank. The rotating liquid, however, in the outer chamber 28 descendsthrough the space 34, encounters the guide vanes 36 which slow itsmomentum and discharges through the outlet 18. Surges in pressure at theinlet 20, first compress the air in the outer chamber 28 beforeafiecting the air in the inner chamber 26. However, very rapidly theforce of the surge is transmitted from the outer chamber to the innerchamber until a balance is achieved.

The described operation, it will be noted, utilizes three factors inabsorbing pressure surges. First, part of the momentum of the enteringliquid is absorbed in the rotation of the liquid around the outerchamber 28. Second, the increased pressure and volume of the surgescompress air at the top of the outer chamber 28. Third, the pressure andvolume of surges are absorbed by compressing air in the upper part ofinner chamber 26. The compression of air in a single chamber to absorbshock for smoothing out the pressure of a pumped liquid is well-known.The novel spinning of the liquid and its combination with aircompression in a plurality of chambers, however, greatly increase theefficiency of the device.

The spinning of the liquid has a flywheel effect in smoothing out thepressure changes. This may be explained as follows. The velocity of aliquid surge as it enters the outer chamber will cause energy to beimparted to the liquid already spinning in said chamber and will cause agreater velocity to be imparted to the liquid rotating against the innersurface of the sidewall 12. Thus, the spinning liquid first receivesenergy and then, when the surge pressure decreases and the liquid slowsdown, imparts energy to liquid discharging from the outlet. Stated inanother way, the kinetic energy of the incoming liquid is first storedin the rotating liquid and then released. Part of the kinetic energy isconverted to potential energy as it enters the spinning liquid. Theconverted potential energy is absorbed by the air in both the inner andouter chambers for later release on reduction of pressure of theincoming liquid.

The embodiments illustrated in FIGS. 4 and 5 differ in only a fewrespects from the embodiment shown in FIGS. 1-3. Accordingly, the samereference numerals are used where the parts are identical, and slightlymodified parts are referenced by the same numeral primed. Since allthree embodiments operate in the same manner, only the differences instructure will be described herein.

The embodiment of FIG. 4 is preferably constructed entirely of aluminum,the cylindrical outer wall 12' being welded at 38 to a dome-shaped topwall 14', and at 40 to a concave bottom wall 16'. The outlet nipple 18'is also connected to the bottom wall by welding as at 42. Similarly, theinner tube 24 is welded at is lower edge 44 to the second bottom wall32, the guide vanes for discharging liquid being omitted. In the innercylinder 24', apertures 30' are fewer in number, but individually largerin area than the corresponding apertures 30 of the FIG. 1 embodiment.The surge tank of FIG. 4, therefore, is a very strong metal tank capableof withstanding higher pressures, and yet is easily fabricated.

The FIG. 5 embodiment is intended for use with liquids being pumped atlower pressures, and is formed entirely of any suitable plasticmaterial. The outer chamber 28 comprising sidewall 12", top wall 14" andinner cylinder 24" are molded in one piece. The sidewall 12" at itslower end is threaded as at 46 for connection to a separate, moldedcup-shaped, bottom wall 16". The bottom wall may have integrally formedtherein, as by molding, a series of vanes 36" which serve as a seat forthe second bottom wall 32", which has a circular protrusion 48 on itsunderside for fitting in the opening formed by the vanes 36". Wall 32"may be firmly secured to vanes 36" by cement or by a friction fit. Inthis manner the second bottom wall 32" is supported from the bottom ofthe tank, and the unit is easily assemblied by then threading the bottom16" onto the threads 46 of sidewall 12". Desirably the cylinder 24" isthickened in the upper portion 50 where it merges into the top wall 14".The spacing 30" between parts 24 and 32" replaces the plurality ofopenings 30 for communicating the chambers 26' and 28'.

It should be noted that the above described surge tanks have thefollowing advantages. The entrance of liquid on a tangent to the outercylindrical wall through a property-sized inlet creates the greatestpossible rotating speed of the liquid within the unit. Thi rotationcreates a suction at the inlet which helps to overcome reverse flow, orreduction in pressure. Rotation of the liquid within the unit creates asource of potential pressure which evens out the pressure surges betweenthe inlet and outlet. The air trapped in both chambers 26, 28 is underpressure which is applied to the liquid at the bottom of the surge tankto assist in smoothing out the discharge flow, part of the pressureincreases being absorbed in the air chambers and subsequently releasedduring the low pressure portions of the pumping cycle. The use of twochambers, or more, for trapping air permits an interaction, the outsidechamber first absorbing a shock without having to overcome the weight ofall of the liquid in the unit. As the spinning liquid is already inmotion in the outer chamber, it will rotate faster and move upwardly inthe outer chamber with small changes in force, or pressure. The air inthe inner chamber absorbs the force from the outer chamber at a slowerrate, but with the result that a surge in pressure is more fullyabsorbed and both chambers act to smooth out pressure variations byimparting pressure to the discharging liquid when the incoming liquidpressure dro s. Since the liquid is being effectively discharged fromthe outside edge of the rotatng liquid, loss of air located in themiddle of the outer chamber is prevented. The rotation of the liquidserves to keep the air away from the discharge path at the outside ofthe outer chamber. The inlet and outlet being at different levelspermits the draining of the surge chamber when air is introduced intothe inlet. Construction of the unit may be one-piece, as shown in FIGS.1-3, since maintenance and internal servicing is unnecessary. The innerchamber prevents liquid which is entering the inlet from disturbing thecone of air in the center of the outer chamber. It also helps to keepthe moving liquid in a smaller annular area which, in turn, increasesthe speed of rotation. A plurality of trapping chambers are provided andair is kept trapped in these chambers without the aid of pistons,diaphragms or balloons, as commonly used in certain conventionalapparatus.

If desired, the device may be constructed without the inner cylinder 24and the second air chamber 26. The unit thus modified will operate,however, with less efficiency.

Although certain embodiments of the invention have been shown anddescribed, it is obvious that many modifications thereof are possible.The invention, therefore, is not to be restricted except insofar as isnecessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

1. A surge tank for moothing pressure changes in a pumped liquid,comprising an outer chamber having an arcuate, continuous sidewall, atop wall closing the outer chamber for trapping air, a bottom wallhaving a liquid outlet disposed centrally therein, a second bottom wallin said chamber spaced above said first bottom wall and having itsperiphery spaced from aid arcuate sidewall, and liquid feed meansdirected tangentially to said arcuate wall and connected to an inlettherein spaced considerably below said top wall and somewhat above saidfirst bottom wall, whereby liquid entering said inlet is caused to swirlabout said arcuate wall, trapping air centrally of said chamber, bothsaid swirling liquid and trapped air contributing to smooth out pressurechanges of the entering liquid, and said swirling liquid in the 5chamber exiting to said outlet through the space between the secondbottom wall and the sidewall.

2. A surge tank according to clam 1, wherein a plurality of curved vanesare disposed vertically between said first bottom wall and said secondbottom wall and extending from the periphery of said second bottom wallto the periphery of said outlet, whereby to direct liquid inwardly fromthe periphery of the second bottom wall to said centrally disposedoutlet.

3. A surge tank according to claim 1, wherein an innerchamber isdisposed within the outer chamber defined by said side, top, and bottomwalls, said inner chamber being completely enclosed except for at leastone opening provided near its bottom communicating with said outerchamber, whereby liquid and air may enter said inner chamber, the airtrapped in said inner'chamber assisting in the smoothing out of pressurechanges of liquid entering said inlet.

4. A surge chamber in accordance with claim 3, wherein said innerchamber comprises an arcuate, continuous sidewall having a common axisof curvature With said sidewall of the outer chamber, the sidewall ofthe inner chamber being closed at its top by said top wall of the outerchamber.

References Cited UNITED STATES PATENTS 2,671,652 3/1954 McCullough139-26 XR 3,082,784 3/1963 McMath 137207 3,146,796 9/1964 Everett137-207 XR 3,292,661 12/1966 Everett 137--207 XR BILLY S. TAYLOR,Primary Examiner.

US. Cl. X.R.

